When concrete floor surfaces and the like are being built, levelling the concrete to a smooth surface after it has been poured is conventionally performed manually by workers using trowels but not only is such manual work inefficient and involve much time, there are also many other problems such as a poor accuracy of leveling, and the difficulty of obtaining workers to perform it.
Because of this, efforts are being made to bring into practical application machines that automatically run across a poured concrete surface after it has been poured and before it has completely hardened and perform the leveling of the concrete.
However, such machines have wheels that run across the poured concrete and disturb the levelness of the surface and have another problem in that the weight of the machine is directly applied to the poured concrete surface and causes other problems of bending or otherwise damaging the steel reinforcement beneath the concrete surface.